In 1999, an outbreak of respiratory disease in Maylasian pigs spread to humans causing febrile encephalitis with a high mortality rate. The cause of this outbreak was identified as Nipah virus (NiV), a relative of Hendra virus that had recently emerged in horses and humans in Australia. The reservoir of both viruses appears to be fruit bats, though the route of transmission to humans and animals is not clear. Since 1999, there have been three outbreaks of NiV in Bangladesh. NiV infection has a high mortality rate in humans, between 40% and 75%, and can cause severe disease in a number of animals of agricultural importance. Therefore, NiV is a candidate for use in bioterror. Our understanding of NiV infection has been hampered by its lethal nature and the need to use BSL-4 conditions to study it. The goal of this application is to make NiV studies easier to perform. Based on knowledge gained from studying another paramyxovirus, respiratory syncytial virus (RSV), a plasmid will be constructed containing a copy of the NiV genome in which the two glycoprotein genes will be replaced with genes for the green fluorescent protein and for an antibiotic resistance gene. The resulting NiV "replicon" should be able to replicate autonomously, as does the existing RSV replicon. Glycoproteins will be provided in trans to generate "single-cycle virus" (SCV), as has been successful for the RSV replicon. Because the Ni-SCV will be infectious for one round only, studies under lower level BSL conditions should be possible. Once the Ni-SCV has been generated, Ni-SCV infection will be compared to infection with NiV. This novel Ni-SCV system will be used to study the pathogenesis of NiV, including the ability of NiV to interfere with the innate immune response. Initial studies will focus on the P/C/V/W genes to dissect the role of each of these proteins in the induction of interferon, in the context of NiV infection. In the future, work with the Ni-SCV could be expanded to explore the induction or suppression of chemokine and cytokine expression, and other pathogenic mechanisms, as well as to provide a means to screen candidate antiviral agents. [unreadable] [unreadable] [unreadable]